709 research outputs found

    Targeted Social Distancing Designs for Pandemic Influenza

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    Local community networks can mitigate pandemic influenza in the absence of vaccine and antiviral drugs

    CFD-DEM modelling of particle ejection by a sensor-based automated sorter

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    © 2015 Elsevier Ltd. Abstract The efficiency of sensor-based automated sorting depends on both correct identification and separation of different types of particles. It is known that the distribution of particles fed to the sorter will affect both of these. When different particles are in close proximity, they can be "agglomerated" or seen as a single particle during identification and also have an increased probability of being unintentionally co-ejected. Both factors will have a negative effect on separation efficiency. The aim of this work was to model the air ejection manifold of a sensor-based automated sorter and to investigate the relationship between particle proximity and unintentional co-ejections. The airflow from a single air ejection valve of a sorter was modelled using computational fluid dynamics (CFD) software and calibrated against a Tomra Sorting Solutions optical sorter. It was found that the air ejection manifold could be accurately represented in CFD code. Particles were modelled using the discrete element method (DEM) software and the effect of particle position, relative to an air ejection valve, on accurate ejection was examined using an integrated CFD-DEM model. The results of these models matched reasonably well with physical measurements. The models created can be used as a basis for the prediction of sorter efficiency

    Rescinding Community Mitigation Strategies in an Influenza Pandemic

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    Thresholds for these strategies reduced the number of days strategies were needed without increasing illness rates

    Wait-learning: Leveraging conversational dead time for second language education

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    Second-language learners are often unable to find time for language practice due to constraints in their daily lives. In this paper, we examine how brief moments of waiting during a person's existing social conversations can be leveraged for second language practice, even if the conversation is exchanged in the first language. We present an instant messaging (IM) prototype, WaitChatter, that supports the notion of wait-learning by displaying contextually relevant foreign language vocabulary and micro-quizzes while the user awaits a response from her conversant. The foreign translations are displayed just-in-time in the context of the conversation to promote incidental learning. In a preliminary study of WaitChatter, we found that participants were able to integrate second language learning into their existing instant messaging activities, and that a particularly opportune time to embed foreign language elements may be immediately after the learner sends a chat message.Lincoln Laborator

    Impedance Characterization of a Model Au/Yttria-Stabilized Zirconia/Au Electrochemical Cell in Varying Oxygen and NO\u3csub\u3e\u3cem\u3ex\u3c/em\u3e\u3c/sub\u3e Concentrations

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    An electrochemical cell [Au/yttria-stabilized zirconia (YSZ)/Au] serves as a model system to investigate the effect of O2 and NOx. Possible mechanisms responsible for the response are presented. Two dense Au electrodes are co-located on the same side of a dense YSZ electrolyte and are separated from the electrolyte by a porous YSZ layer, present only under the electrodes. While not completely understood, the porous layer appears to result in enhanced NOx response. Impedance data were obtained over a range of frequencies 0.1 Hz to 1 MHz, temperatures 600–700°C, and oxygen 2–18.9% and NOx 10–100 ppm concentrations. Spectra were fit with an equivalent circuit, and values of the circuit elements were evaluated. In the absence of NOx, the effect of O2 on the low-frequency arc resistance could be described by a power law, and the temperature dependence by a single apparent activation energy at all O2 concentrations. When both O2 and NOx were present, however, the power-law exponent varied as a function of both temperature and concentration, and the apparent activation energy also showed dual dependence. Adsorption mechanisms are discussed as possibilities for the rate-limiting steps. Implications for impedancemetric NOx sensing are also discussed

    Performance of the PROMIS in Patients After Anterior Cruciate Ligament Reconstruction

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    Background: The Patient-Reported Outcomes Measurement Information System (PROMIS) is designed to advance patient-reported outcome (PRO) instruments by utilizing question banks for major health domains. Purpose: To compare the responsiveness and construct validity of the PROMIS physical function computer adaptive test (PF CAT) with current PRO instruments for patients before and up to 2 years after anterior cruciate ligament (ACL) reconstruction. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Initially, 157 patients completed the PROMIS PF CAT, Short Form-36 Health Survey (SF-36 physical function [PF] and general health [GH]), Marx Activity Rating Scale (MARS), Knee injury and Osteoarthritis Outcome Score (KOOS activities of daily living [ADL], sport, and quality of life [QOL]), and EuroQol-5 dimensions questionnaire (EQ-5D) at 6 weeks, 6 months, and 2 years after ACL reconstruction. Correlations between instruments, ceiling and floor effects, effect sizes (Cohen d), and standardized response means to describe responsiveness were evaluated. Subgroup analyses compared participants with and without additional arthroscopic procedures using linear mixed models. Results: At baseline, 6 weeks, and 6 months, the PROMIS PF CAT showed excellent or excellent-good correlations with the SF-36 PF (r = 0.75-0.80, P \u3c .01), KOOS-ADL (r = 0.63-0.70, P \u3c .01), and KOOS-sport (r = 0.32-0.69, P \u3c .01); excellent-good correlation with the EQ-5D (r = 0.60-0.71, P \u3c .01); and good correlation with the KOOS-QOL (r = 0.52-0.58, P \u3c .01). As expected, there were poor correlations with the MARS (r = 0.00-0.24, P \u3c .01) and SF-36 GH (r = 0.16-0.34, P \u3c .01 ). At 2 years, the PROMIS PF CAT showed good to excellent correlations with all PRO instruments (r = 0.42-0.72, P \u3c .01), including the MARS (r = 0.42, P \u3c .01), indicating frequent return to preinjury function. The PROMIS PF CAT had the fewest ceiling or floor effects of all instruments tested, and patients answered, on average, 4 questions. There was no significant difference in baseline physical function scores between subgroups; at follow-up, all groups showed improvements in scores that were not statistically different. Conclusion: The PROMIS PF CAT is a valid tool to assess outcomes after ACL reconstruction up to 2 years after surgery, demonstrating the highest responsiveness to change with the fewest ceiling and floor effects and a low time burden among all instruments tested. The PROMIS PF CAT is a beneficial alternative for assessing physical function in adults before and after ACL reconstruction

    MODELING TRIBAL LEADERSHIP DYNAMICS: AN OPINION DYNAMICS MODEL OF PASHTUN LEADERSHIP SELECTION

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    We propose a new approach to modeling the selection of leaders in Pashtun tribal society. Pashtuns are the largest tribal group in Afghanistan. In traditional Pashtun society, leadership is manifested as an informal power system where potential leaders gain and maintain their position by means of group consensus. Leadership power is spread over three areas of influence resulting in a triad of leadership roles. These leaders compete, vying for power and control based on public opinion. The addition of extremists into this system who utilize threats of harm to gain power disrupts the traditional system, altering the balance of power. In this research we implement a bounded confidence opinion dynamics model to describe the dynamics of Pashtun leadership selection and to describe the changes resulting from the addition of extremists to the system. Keywords

    Performance of the PROMIS After Operative Interventions for Shoulder Instability

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    Background: The Patient-Reported Outcomes Measurement Information System (PROMIS) was developed to capture patient-reported outcomes (PROs) in an efficient manner. Few studies have assessed this instrument postoperatively. Purpose: To compare the PROMIS Physical Function computer adaptive test (PROMIS PF CAT) and Upper Extremity (PROMIS UE) item bank to other previously validated PRO instruments and to evaluate ceiling and floor effects and construct validity responsiveness in patients who underwent operative interventions for shoulder instability. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A total of 72 patients who underwent operative interventions for shoulder instability completed the American Shoulder and Elbow Surgeons (ASES) assessment form, Marx shoulder activity scale (Marx), 36-Item Short Form Health Survey physical function (SF-36 PF) and general health (SF-36 GH), Western Ontario Shoulder Instability Index (WOSI), PROMIS PF CAT, and PROMIS UE before surgery and then at 6 weeks and 6 months postoperatively. Correlation coefficients were calculated among these tools. The effect size of change was also calculated for each tool at each time point. A total of 91 patients who had also undergone surgery for shoulder instability completed these PRO instruments 2 years postoperatively. The percentage of patients hitting the ceiling and floor effects of each of the PRO instruments was calculated at all time points. Results: The PROMIS PF CAT demonstrated excellent-good correlation with the SF-36 PF at all postoperative time points (0.61 at 6 weeks, 0.68 at 6 months, and 0.64 at 2 years; P \u3c .01 for all). The PROMIS UE showed excellent correlation with the ASES at 6 weeks postoperatively (0.73, P \u3c .01). Both the PROMIS PF CAT and PROMIS UE demonstrated the ability to detect change after surgical interventions with a medium to large effect size. The PROMIS UE demonstrated a ceiling effect at 6 months (68.1%) and 2 years (67.0%) postoperatively. The PROMIS PF CAT demonstrated no ceiling effect at any time point. Conclusion: The PROMIS PF CAT demonstrated good to excellent correlation with other previously validated PRO instruments that assess physical function in patients with shoulder instability postoperatively. The PROMIS UE demonstrated good correlation with other PRO tools but had a significant ceiling effect and is not recommended for this patient population. Both tools demonstrated an ability to detect change after surgical interventions with a good effect size

    Interferometric Constraints on Quantum Geometrical Shear Noise Correlations

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    Final measurements and analysis are reported from the first-generation Holometer, the first instrument capable of measuring correlated variations in space-time position at strain noise power spectral densities smaller than a Planck time. The apparatus consists of two co-located, but independent and isolated, 40 m power-recycled Michelson interferometers, whose outputs are cross-correlated to 25 MHz. The data are sensitive to correlations of differential position across the apparatus over a broad band of frequencies up to and exceeding the inverse light crossing time, 7.6 MHz. By measuring with Planck precision the correlation of position variations at spacelike separations, the Holometer searches for faint, irreducible correlated position noise backgrounds predicted by some models of quantum space-time geometry. The first-generation optical layout is sensitive to quantum geometrical noise correlations with shear symmetry---those that can be interpreted as a fundamental noncommutativity of space-time position in orthogonal directions. General experimental constraints are placed on parameters of a set of models of spatial shear noise correlations, with a sensitivity that exceeds the Planck-scale holographic information bound on position states by a large factor. This result significantly extends the upper limits placed on models of directional noncommutativity by currently operating gravitational wave observatories.Comment: Matches the journal accepted versio
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